<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
    .app{
      width: 12000px;
      height: 2600px;
    }
    .box{
      position: sticky;
      top: 10px;/*最小值*/
	  left: 40px;
      width: 50px;
      height: 50px; 
      background: #ff001c;
    }
  </style>
</head>
<body>
<div class="app">
<div style="height: 120px; background-color: blue;"></div>
  <div class="box">
  </div>
</div>
</body>
</html>